In the polymerization of .alpha.-olefins such as propylene, etc. by the Ziegler Natta catalyst of the prior art, a chain-transfer reaction or chain termination reaction takes place and accordingly, it is difficult to modify one of the terminals of the polymer with substituents, etc.
The object of the present invention is to provide such a linear polyolefin wherein one of the terminals of polypropylene or ethylene-propylene random copolymer is modified with methacrylic acid (acrylic acid) derivative units or styrene derivative units to give a substantially monodispersed system.